Portable mass storage devices with ever increasing storage capacity are being employed more and more frequently in a great variety of electronic devices. There can be stored thereon digital contents or text, image, audio or video data or the like. Portable mass storage devices have the advantage here that they can be read and optionally written by different electronic devices, such as PCs, PDAs, smartphones, digital cameras, audio devices, etc. The portable mass storage devices thus permit a simple saving and transporting of digital contents.
For portable mass storage devices there have been developed different standards whose degree of acceptance varies. Widespread types of mass storage devices are MultiMediaCards (MMC), Secure Digital memory cards (SD cards), microSD cards, memory sticks (USB sticks), but also CDs, DVDs, etc.
It is also known to additionally equip portable data carriers of the above-mentioned type with additional information, in particular security functions, in order for example to protect digital contents of the memory from unauthorized access. In this connection there is known from the applicant's WO 2008/058741 A2 a control system for accesses to a portable storage data carrier which has not only a secure smart card chip but also a conventional mass storage, in particular a flash memory, which is not specially protected. Through the interaction of routing information with a controller arranged on the card and set up to evaluate the routing information there is created a mechanism that allows the controller to route data incoming on the portable storage data carrier either to the flash memory or to the smart card chip. The routing information comprises an identifier unique to the smart card chip and preferably present in the form of a character string of predetermined length. The routing information can furthermore contain further information about sender and destination unit of application data. The accesses to the storage element are effected by means of standard commands of the employed operating system, in particular employing common write and read commands, search commands, identification commands, etc. In so doing there can be effected a return transmission of responses of the additional module to the terminal using a temporary working address in the storage element under which the response is made available in the storage data carrier. Through the control system described in this print it is possible to selectively address the main or additional function of the portable storage data carrier without any special drivers having to be respectively developed and set up.
In connection with the access to intelligent memory cards of all kinds, in particular SD cards, MMC cards, which additionally include a smart card chip, it is known from U.S. Pat. No. 7,334,077 B2 to establish a detection mechanism on the memory cards which interacts with a flag sequence which is inserted into conventional access commands. This permits the establishment of new commands and special operations on the storage data carrier without having to perform extensive changes on the drivers. The flag sequence here can be any string of data and is e.g. set in the data field of standard, write and read commands. The flag sequence can furthermore contain an indicator for the execution of a special operation. When the detection mechanism detects such a flag sequence in an access command, it does not execute the access command, but performs the command execution according to a mode of operation deposited on the memory card and executes in particular a special operation.
From WO 2007/076214 A2 there is further known a communication method between a terminal (host) and a data carrier via a reader/adapter when the terminal and the data carrier utilize different transmission protocols. In said communication method, commands are formed according to the local protocol of the card directly in the terminal and embedded in a data field of commands typical of the terminal. In the data carrier the embedded commands are extracted and executed. To signal the presence of embedded commands to the card, they are prefixed with a signature.